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Background: Ariidae species play a significant role as fishing resources in the Amazon region. However, the family's systematic classification is notably challenging, particularly regarding species delimitation within certain genera. This difficulty arises from pronounced morphological similarities among species, posing obstacles to accurate species recognition. Methods: Following morphological identification, mitochondrial markers (COI and Cytb) were employed to assess the diversity of Ariidae species in the Amazon. Results: Our sampling efforts yielded 12 species, representing 92% of the coastal Amazon region's diversity. Morphological identification findings were largely corroborated by molecular data, particularly for species within the Sciades and Bagre genera. Nonetheless, despite morphological support, Cathorops agassizii and Cathorops spixii displayed minimal genetic divergence (0.010). Similarly, Notarius quadriscutis and Notarius phrygiatus formed a single clade with no genetic divergence, indicating mitochondrial introgression. For the majority of taxa examined, both COI and Cytb demonstrated efficacy as DNA barcodes, with Cytb exhibiting greater polymorphism and resolution. Consequently, the molecular tools utilized proved highly effective for species discrimination and identification. [ABSTRACT FROM AUTHOR]

Background Ariidae species play a significant role as fishing resources in the Amazon region. However, the family’s systematic classification is notably challenging, particularly regarding species delimitation within certain genera. This difficulty arises from pronounced morphological similarities among species, posing obstacles to accurate species recognition. Methods Following morphological identification, mitochondrial markers (COI and Cytb) were employed to assess the diversity of Ariidae species in the Amazon. Results Our sampling efforts yielded 12 species, representing 92% of the coastal Amazon region’s diversity. Morphological identification findings were largely corroborated by molecular data, particularly for species within the Sciades and Bagre genera. Nonetheless, despite morphological support, Cathorops agassizii and Cathorops spixii displayed minimal genetic divergence (0.010). Similarly, Notarius quadriscutis and Notarius phrygiatus formed a single clade with no genetic divergence, indicating mitochondrial introgression. For the majority of taxa examined, both COI and Cytb demonstrated efficacy as DNA barcodes, with Cytb exhibiting greater polymorphism and resolution. Consequently, the molecular tools utilized proved highly effective for species discrimination and identification.

The European eel (Anguilla anguilla) has declined by over 90% since the early 1980s and has been listed as critically endangered. Yet, despite strict export bans from the European Union, the European eel is still sold illegally in many countries. Efforts to monitor the trade of European eels have been primarily concentrated in Asian markets where concerningly high rates of European eel have been reported. Comparably fewer studies have assessed the identities of eel samples from the United States (US), despite the obvious implications for eel conservation. To address this knowledge gap, we purchased 137 eel products (134 freshwater eels and three saltwater eels) from grocers, sushi bars, and restaurants in nine states across the US from 2019 to 2021. Seven samples (5.2%) labeled as freshwater eels (or "unagi") were identified as European eels using a combination of mitochondrial (cytochrome b) and nuclear (18S rRNA) restriction digestion assays, a fast and inexpensive molecular tool for seafood identification that can identify hybrids between European eels (A. anguilla) and American eels (A. rostrata). No hybrids between European and American eels were found and all seven samples identified with restriction digestion as European eels were confirmed by sequencing of cytochrome b and 18S rRNA. Frequency of European eels in US markets did not significantly correlate with state or retail type. Although illegal eel exports are likely reaching US consumers, the frequency of European eel samples in this study of the US market is much lower than found in other non-European countries. [ABSTRACT FROM AUTHOR]

The European eel (Anguilla anguilla) has declined by over 90% since the early 1980s and has been listed as critically endangered. Yet, despite strict export bans from the European Union, the European eel is still sold illegally in many countries. Efforts to monitor the trade of European eels have been primarily concentrated in Asian markets where concerningly high rates of European eel have been reported. Comparably fewer studies have assessed the identities of eel samples from the United States (US), despite the obvious implications for eel conservation. To address this knowledge gap, we purchased 137 eel products (134 freshwater eels and three saltwater eels) from grocers, sushi bars, and restaurants in nine states across the US from 2019 to 2021. Seven samples (5.2%) labeled as freshwater eels (or “unagi”) were identified as European eels using a combination of mitochondrial (cytochrome b) and nuclear (18S rRNA) restriction digestion assays, a fast and inexpensive molecular tool for seafood identification that can identify hybrids between European eels (A. anguilla) and American eels (A. rostrata). No hybrids between European and American eels were found and all seven samples identified with restriction digestion as European eels were confirmed by sequencing of cytochrome b and 18S rRNA. Frequency of European eels in US markets did not significantly correlate with state or retail type. Although illegal eel exports are likely reaching US consumers, the frequency of European eel samples in this study of the US market is much lower than found in other non-European countries.

Calanoid copepod Peudodiaptomus marinus Sato, 1913 was first recorded in Sevastopol Bay in the northern Black Sea in September 2016. We performed regular observations of this new invasive species between October 2016 and December 2018. We conducted bi-weekly plankton sampling at three stations located within or adjacent to Sevastopol Bay. This is the first paper to combine (i) a detailed morphological study, (ii) molecular genetic analysis, and (iii) an investigation of P. marinus seasonal dynamics and interannual abundance variability in the coastal Black Sea. Our morphological research showed similarities between Pseudodiaptomus specimens and existing P. marinus illustrations and descriptions. Our morphological analysis results were confirmed using molecular genetic studies. Based on the genetic variability of ITS2 and cytb, we found that all investigated specimens from Sevastopol Bay belonged to P. marinus. Investigations of P. marinus seasonal and interannual abundance variability showed the same seasonal patterns throughout the studied period, with a higher seasonal abundance from October to November and one pronounced density peak in autumn. The highest abundances (2,000 ind m–3 at the mouth of the bay and more than 5,000 ind m–3at its centre) were recorded in November 2018. In the samples, we found adults of both sexes, including ovigerous females, copepodites I–V, and nauplii, suggesting that the species reproduce in Sevastopol Bay. Our research indicated that P. marinus is a new non-indigenous species (NIS) in the Black Sea, and we will discuss a possible vector of its introduction into this basin.

The Gidran is a native Hungarian horse breed that has approached extinction several times. Phylogenetic analysis of two mitochondrial markers (D-loop and cytochrome-b) was performed to determine the genetic characterization of the Gidran for the first time as well as to detect errors in the management of the Gidran stud book. Sequencing of 686 bp of CYTB and 202 bp of the D-loop in 260 mares revealed 24 and 32 haplotypes, respectively, among 31 mare families. BLAST analysis revealed six novel CYTB and four D-loop haplotypes that have not been previously reported. The Gidran mares showed high haplotype (CYTB: 0.8735 ± 0.011; D-loop: 0.9136 ± 0.008) and moderate nucleotide (CYTB: 0.00472 ± 0.00017; D-loop: 0.02091 ± 0.00068) diversity. Of the 31 Gidran mare families, only 15 CYTB (48.4%) and 17 D-loop (54.8%) distinct haplotypes were formed using the two markers separately. Merged markers created 24 (77.4%) mare families, which were in agreement with the mare families in the stud book. Our key finding was that the Gidran breed still possesses high genetic diversity despite its history. The obtained haplotypes are mostly consistent with known mare families, particularly when the two mtDNA markers were merged. Our results could facilitate conservation efforts for preserving the genetic diversity of the Gidran.

Calanoid copepod Peudodiaptomus marinus Sato, 1913 was first recorded in Sevastopol Bay in the northern Black Sea in September 2016. We performed regular observations of this new invasive species between October 2016 and December 2018. We conducted bi-weekly plankton sampling at three stations located within or adjacent to Sevastopol Bay. This is the first paper to combine (i) a detailed morphological study, (ii) molecular genetic analysis, and (iii) an investigation of P. marinus seasonal dynamics and interannual abundance variability in the coastal Black Sea. Our morphological research showed similarities between Pseudodiaptomus specimens and existing P. marinus illustrations and descriptions. Our morphological analysis results were confirmed using molecular genetic studies. Based on the genetic variability of ITS2 and cytb , we found that all investigated specimens from Sevastopol Bay belonged to P. marinus. Investigations of P. marinus seasonal and interannual abundance variability showed the same seasonal patterns throughout the studied period, with a higher seasonal abundance from October to November and one pronounced density peak in autumn. The highest abundances (2,000 ind m -3 at the mouth of the bay and more than 5,000 ind m -3 at its centre) were recorded in November 2018. In the samples, we found adults of both sexes, including ovigerous females, copepodites I-V, and nauplii, suggesting that the species reproduce in Sevastopol Bay. Our research indicated that P. marinus is a new non-indigenous species (NIS) in the Black Sea, and we will discuss a possible vector of its introduction into this basin., Competing Interests: The authors declare there are no competing interests., (©2020 Gubanova et al.)

The Gidran is a native Hungarian horse breed that has approached extinction several times. Phylogenetic analysis of two mitochondrial markers (D-loop and cytochrome-b) was performed to determine the genetic characterization of the Gidran for the first time as well as to detect errors in the management of the Gidran stud book. Sequencing of 686 bp of CYTB and 202 bp of the D-loop in 260 mares revealed 24 and 32 haplotypes, respectively, among 31 mare families. BLAST analysis revealed six novel CYTB and four D-loop haplotypes that have not been previously reported. The Gidran mares showed high haplotype (CYTB: 0.8735 ± 0.011; D-loop: 0.9136 ± 0.008) and moderate nucleotide (CYTB: 0.00472 ± 0.00017; D-loop: 0.02091 ± 0.00068) diversity. Of the 31 Gidran mare families, only 15 CYTB (48.4%) and 17 D-loop (54.8%) distinct haplotypes were formed using the two markers separately. Merged markers created 24 (77.4%) mare families, which were in agreement with the mare families in the stud book. Our key finding was that the Gidran breed still possesses high genetic diversity despite its history. The obtained haplotypes are mostly consistent with known mare families, particularly when the two mtDNA markers were merged. Our results could facilitate conservation efforts for preserving the genetic diversity of the Gidran.